Foundations of Prenatal Genetic Testing: Understanding Screening, Diagnosis, and Counseling

A prenatal genetic test result can be one of the most emotionally charged pieces of information a person receives during pregnancy. Understanding what that result actually means — what was tested, how confident the result is, and what the next step might be — requires a baseline literacy in how these tests work, what they can and cannot tell you, and what genetic counseling is designed to do. By the end of this course you will be able to distinguish between screening tests and diagnostic tests, explain how non-invasive prenatal testing (NIPT) works and what conditions it screens for, describe the procedures of amniocentesis and chorionic villus sampling (CVS) and why they carry a small procedural risk, understand what aneuploidy screening means and the conditions most commonly tested, and explain the role of genetic counseling in interpreting results and supporting informed decision-making. What you will learn: - Screening versus diagnostic tests: what a positive screen means and why it is not the same as a diagnosis - NIPT: how cell-free fetal DNA in maternal blood is analyzed, what conditions it screens for, and its limitations - First-trimester combined screening: nuchal translucency ultrasound plus blood markers - Amniocentesis: procedure timing, what is analyzed, diagnostic accuracy, and procedural risk - Chorionic villus sampling (CVS): how it differs from amniocentesis, when it is offered, and what it can detect - Aneuploidy screening: trisomy 21 (Down syndrome), trisomy 18, trisomy 13, and sex chromosome conditions - Carrier screening: what it tests for, who it is offered to, and how it differs from fetal testing - The role of genetic counseling: how counselors help patients interpret results, understand options, and process information The course is organized as a series of structured readings, each covering one test type or counseling concept, followed by worked case examples showing how a typical result is communicated and what questions follow. Reflection prompts encourage readers to consider what information is most important to them in advance of testing. The course does not advocate for or against any testing decision. This course is designed for individuals who are pregnant, planning a pregnancy, or supporting someone who is, and who want to approach genetic testing conversations with their care team from a position of knowledge. No prior medical background is required. This course is informational and educational; it does not substitute for consultation with a licensed genetic counselor, obstetrician, or Maternal-Fetal Medicine specialist familiar with your specific circumstances.